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3 Projects

  • Canada
  • UK Research and Innovation
  • 2009
  • 2011

  • Funder: UKRI Project Code: NE/F021399/1
    Funder Contribution: 222,230 GBP

    This project will quantify the effect of surface generated melt-water fluctuations on ice motion at the margin of the Greenland Ice Sheet (GrIS). More specifically, it will provide data that will enable ice-sheet modellers to improve their predictions of the future contribution of the GrIS to sea level rise in response to a warming world. To achieve this aim requires a dedicated field campaign to the GrIS to investigate seasonal ice flow dynamics and runoff processes along flow parallel transects extending from the ice sheet margin to the equilibrium line altitude (ELA) at both tidewater and land-terminating glaciers. The greatest store of fresh water in the northern hemisphere - equivalent to 7m of eustatic sea level rise - is held within the Greenland Ice Sheet (GrIS), and yet its present and future contribution to sea level is poorly constrained (IPCC, 2007). Recent observations suggest that mass loss near the margin of the GrIS is accelerating through a combination of increased surface melting (e.g. Steffen et al, 2004) and dynamic thinning (e.g. Rignot and Kanagaratnam, 2006). However, the key processes controlling dynamic thinning have yet to be identified (Alley et al, 2005), and in consequence, are not incorporated in the ice-sheet models which form the basis of the IPCC sea level projections. This in part reflects the fact that the satellite data that has revealed the widespread speed-up of glaciers cannot be acquired at the temporal resolution needed to resolve the causal mechanisms. Our present understanding of GrIS mass balance is especially complicated by uncertainties in the sensitivity of ice-marginal dynamics to changes in melt-water induced lubrication resulting from penetration of supraglacial melt-waters to the glacier bed (Zwally et al, 2002). Recent observations on the GrIS Shepherd et al, in review) reveal, over a five day period in July, a strong and direct coupling between surface hydrology and dynamics where diurnal fluctuations in velocity of >100% occur and where maximum daily velocities scale with temperature. Such observations confirm the need to acquire hydrological and dynamic data at high temporal (sub-hourly) and spatial resolution throughout the year to parameterise the coupling between ice melting and flow. This project will collect data at the necessary resolution to quantify the relationship between melt-water production and ice sheet dynamics thereby enabling ice-sheet modellers to improve predictions of the GrIS's response to climate change. We will conduct ground based experiments along two flow-parallel transects at the western margin of the GrIS in adjacent land and marine terminating drainage basins to address the following objectives: 1. Is there a temporal and spatial pattern to any hydrology-dynamic link associated with the seasonal evolution of the supraglacial drainage system (including supraglacial lakes)? 2. Over what area does surface generated meltwater penetrate to the base of the ice sheet? 3. Is there a relationship between the volume of meltwater input at the glacier surface and the magnitude of the dynamic response? 4. Do tidewater and land-terminating glaciers behave differently during the course of a melt-season? Field campaigns will be undertaken during 2008 and 2009 to determine: 1) The rate, extent and duration of melt. 2) The temporal and spatial variations in water volumes stored in and released from supraglacial lakes and delivered to freely draining moulins. 3) The seasonal, diurnal and hourly variations in ice dynamics. 4) The variations in proglacial discharge and water chemistry (at Russell Glacier). As a result of our work, it will be possible to determine whether ice dynamics at the margin of the GrIS is significantly affected by lubrication of the glacier bed following the drainage of surface derived meltwaters. Our results will be delivered to ice sheet modellers to help them constrain predictions for the future of the GrIS

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  • Funder: UKRI Project Code: BB/G004803/1
    Funder Contribution: 272,247 GBP

    The human brain uses small differences between the images reaching our two eyes to perceive the three-dimensional shape of the world around us. In order to detect these differences, known as binocular disparities, the brain must find points in one eye's image that match to points in the other eye's image. However, for any single point in an image, the brain is often forced to choose between multiple matches. The problem of finding the correct match from amongst these alternatives is known as the correspondence problem. This problem can be simplified by making assumptions about the typical shape of objects in the world, and by finding matches between different kinds of basic tokens. For example, the number of alternative solutions to the correspondence problem will be far greater if the brain uses single points of light as a basic token for matching, compared to a case where a more complex token, such as a shape or texture, is used. Furthermore, these complex tokens can be based on different kinds of information. The research proposed here examines how matching tokens based on different forms of information can be used by the brain to solve the correspondence problem. Specifically, we shall examine how the brain may solve the correspondence problem using tokens derived from mechanisms sensitive to changes in light and dark (i.e. changes in luminance), and mechanisms sensitive to changes in texture. We shall develop computer simulations of the processes used by the brain to solve the correspondence problem and measure disparity. These simulations will show how the use of different basic information for matching (i.e. changes in luminance and changes in texture) can change the nature of the correspondence problem. We shall discover whether the combined use of texture- and luminance-based matching tokens can help to reduce noise in disparity measurement and whether the use of texture-based matching can reduce the number of available solutions to the correspondence problem. Following this, we shall examine whether the brain actually makes use of the combined information available from texture and luminance. By presenting human participants with images containing disparities defined by both texture and luminance, we shall establish whether the human brain actually uses these different types of information to reduce noise, or improve its ability to solve the correspondence problem. In addition to examining whether using luminance and texture information to measure disparity helps the brain to reduce noise and simplify the correspondence problem, we shall also examine whether sensitivity to these different types of image information can help the brain to detect discontinuities in depth. Depth discontinuities arise when depth changes sharply across a small area, such as when an observer's view of one object is partially obscured by another object in front of it. The processing of texture-based disparities may help in the detection of depth discontinuities since different objects often differ in texture. We shall establish whether information of this kind may actually be useful in the detection of depth discontinuities, and whether human observers actually use this information.

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  • Funder: UKRI Project Code: EP/H023836/1
    Funder Contribution: 195,938 GBP

    The aim of Silicon photonics is nothing less than the complete convergence of optics and electronics. In the first instance this endeaviour was aimed at oversoming the limitations imposed by nature in the transport of information using electrons. However, the work has already thrown up more general optical technologies which can be minaturised onto silicon chips. In fact, engineers are slowly building a whole optics toolbox on silicon, including detectors, modulators and spectrometers. The international consortium assembled for the current work have already made significant progress in providing the long sought after on-chip light source. The feasibility studies proposed here are aimed at building on the existing expertise found in the consortium and elsewhere to apply these technologies to the optical detection and manipulation of single biomolecules in a way than can be miniaturised giving devices that have such functionalities on a silicon chip. The impact of the work will be enhanced by the fact that the approaches used are compatible with those used during the manufacture of standard silicon chips and that the end products can be mass produced (at costs measured in cents per unit) for personalised health care applications in every home, doctor's surgery/pharmacist; for the detection of low level atmosphere or water born pollutants or for counter terrorism/military applications

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Advanced search in
Projects
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includes
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The following results are related to Canada. Are you interested to view more results? Visit OpenAIRE - Explore.
3 Projects
  • Funder: UKRI Project Code: NE/F021399/1
    Funder Contribution: 222,230 GBP

    This project will quantify the effect of surface generated melt-water fluctuations on ice motion at the margin of the Greenland Ice Sheet (GrIS). More specifically, it will provide data that will enable ice-sheet modellers to improve their predictions of the future contribution of the GrIS to sea level rise in response to a warming world. To achieve this aim requires a dedicated field campaign to the GrIS to investigate seasonal ice flow dynamics and runoff processes along flow parallel transects extending from the ice sheet margin to the equilibrium line altitude (ELA) at both tidewater and land-terminating glaciers. The greatest store of fresh water in the northern hemisphere - equivalent to 7m of eustatic sea level rise - is held within the Greenland Ice Sheet (GrIS), and yet its present and future contribution to sea level is poorly constrained (IPCC, 2007). Recent observations suggest that mass loss near the margin of the GrIS is accelerating through a combination of increased surface melting (e.g. Steffen et al, 2004) and dynamic thinning (e.g. Rignot and Kanagaratnam, 2006). However, the key processes controlling dynamic thinning have yet to be identified (Alley et al, 2005), and in consequence, are not incorporated in the ice-sheet models which form the basis of the IPCC sea level projections. This in part reflects the fact that the satellite data that has revealed the widespread speed-up of glaciers cannot be acquired at the temporal resolution needed to resolve the causal mechanisms. Our present understanding of GrIS mass balance is especially complicated by uncertainties in the sensitivity of ice-marginal dynamics to changes in melt-water induced lubrication resulting from penetration of supraglacial melt-waters to the glacier bed (Zwally et al, 2002). Recent observations on the GrIS Shepherd et al, in review) reveal, over a five day period in July, a strong and direct coupling between surface hydrology and dynamics where diurnal fluctuations in velocity of >100% occur and where maximum daily velocities scale with temperature. Such observations confirm the need to acquire hydrological and dynamic data at high temporal (sub-hourly) and spatial resolution throughout the year to parameterise the coupling between ice melting and flow. This project will collect data at the necessary resolution to quantify the relationship between melt-water production and ice sheet dynamics thereby enabling ice-sheet modellers to improve predictions of the GrIS's response to climate change. We will conduct ground based experiments along two flow-parallel transects at the western margin of the GrIS in adjacent land and marine terminating drainage basins to address the following objectives: 1. Is there a temporal and spatial pattern to any hydrology-dynamic link associated with the seasonal evolution of the supraglacial drainage system (including supraglacial lakes)? 2. Over what area does surface generated meltwater penetrate to the base of the ice sheet? 3. Is there a relationship between the volume of meltwater input at the glacier surface and the magnitude of the dynamic response? 4. Do tidewater and land-terminating glaciers behave differently during the course of a melt-season? Field campaigns will be undertaken during 2008 and 2009 to determine: 1) The rate, extent and duration of melt. 2) The temporal and spatial variations in water volumes stored in and released from supraglacial lakes and delivered to freely draining moulins. 3) The seasonal, diurnal and hourly variations in ice dynamics. 4) The variations in proglacial discharge and water chemistry (at Russell Glacier). As a result of our work, it will be possible to determine whether ice dynamics at the margin of the GrIS is significantly affected by lubrication of the glacier bed following the drainage of surface derived meltwaters. Our results will be delivered to ice sheet modellers to help them constrain predictions for the future of the GrIS

    visibility537
    visibilityviews537
    downloaddownloads191
    Powered by Usage counts
    more_vert
  • Funder: UKRI Project Code: BB/G004803/1
    Funder Contribution: 272,247 GBP

    The human brain uses small differences between the images reaching our two eyes to perceive the three-dimensional shape of the world around us. In order to detect these differences, known as binocular disparities, the brain must find points in one eye's image that match to points in the other eye's image. However, for any single point in an image, the brain is often forced to choose between multiple matches. The problem of finding the correct match from amongst these alternatives is known as the correspondence problem. This problem can be simplified by making assumptions about the typical shape of objects in the world, and by finding matches between different kinds of basic tokens. For example, the number of alternative solutions to the correspondence problem will be far greater if the brain uses single points of light as a basic token for matching, compared to a case where a more complex token, such as a shape or texture, is used. Furthermore, these complex tokens can be based on different kinds of information. The research proposed here examines how matching tokens based on different forms of information can be used by the brain to solve the correspondence problem. Specifically, we shall examine how the brain may solve the correspondence problem using tokens derived from mechanisms sensitive to changes in light and dark (i.e. changes in luminance), and mechanisms sensitive to changes in texture. We shall develop computer simulations of the processes used by the brain to solve the correspondence problem and measure disparity. These simulations will show how the use of different basic information for matching (i.e. changes in luminance and changes in texture) can change the nature of the correspondence problem. We shall discover whether the combined use of texture- and luminance-based matching tokens can help to reduce noise in disparity measurement and whether the use of texture-based matching can reduce the number of available solutions to the correspondence problem. Following this, we shall examine whether the brain actually makes use of the combined information available from texture and luminance. By presenting human participants with images containing disparities defined by both texture and luminance, we shall establish whether the human brain actually uses these different types of information to reduce noise, or improve its ability to solve the correspondence problem. In addition to examining whether using luminance and texture information to measure disparity helps the brain to reduce noise and simplify the correspondence problem, we shall also examine whether sensitivity to these different types of image information can help the brain to detect discontinuities in depth. Depth discontinuities arise when depth changes sharply across a small area, such as when an observer's view of one object is partially obscured by another object in front of it. The processing of texture-based disparities may help in the detection of depth discontinuities since different objects often differ in texture. We shall establish whether information of this kind may actually be useful in the detection of depth discontinuities, and whether human observers actually use this information.

    visibility4
    visibilityviews4
    downloaddownloads4
    Powered by Usage counts
    more_vert
  • Funder: UKRI Project Code: EP/H023836/1
    Funder Contribution: 195,938 GBP

    The aim of Silicon photonics is nothing less than the complete convergence of optics and electronics. In the first instance this endeaviour was aimed at oversoming the limitations imposed by nature in the transport of information using electrons. However, the work has already thrown up more general optical technologies which can be minaturised onto silicon chips. In fact, engineers are slowly building a whole optics toolbox on silicon, including detectors, modulators and spectrometers. The international consortium assembled for the current work have already made significant progress in providing the long sought after on-chip light source. The feasibility studies proposed here are aimed at building on the existing expertise found in the consortium and elsewhere to apply these technologies to the optical detection and manipulation of single biomolecules in a way than can be miniaturised giving devices that have such functionalities on a silicon chip. The impact of the work will be enhanced by the fact that the approaches used are compatible with those used during the manufacture of standard silicon chips and that the end products can be mass produced (at costs measured in cents per unit) for personalised health care applications in every home, doctor's surgery/pharmacist; for the detection of low level atmosphere or water born pollutants or for counter terrorism/military applications

    more_vert
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